[Arizhel]

There's another factor to the coffee shops IMO: who the people are.

In an open-plan office, the people around you are usually your coworkers, the people you see every day and know personally. In a coffee shop, they're usually total strangers, people you might see occasionally at that shop at best, and very likely you'll never see them again.

Also, the strangers at the coffee shop don't care what you're looking at on your laptop, or if you're getting any work done. Coworkers might. Also, strangers at a coffee shop are unlikely to interrupt you; coworkers are very likely to. So at the coffee shop, it's entirely possible to be around other humans without being forced to socialize with them, but not at work.